[PATCH 4.4 040/108] cifs: Fix missing put_xid in cifs_file_strict_mmap

From: Greg Kroah-Hartman
Date: Thu Feb 15 2018 - 10:22:22 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

commit f04a703c3d613845ae3141bfaf223489de8ab3eb upstream.

If cifs_zap_mapping() returned an error, we would return without putting
the xid that we got earlier. Restructure cifs_file_strict_mmap() and
cifs_file_mmap() to be more similar to each other and have a single
point of return that always puts the xid.

Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/cifs/file.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3241,20 +3241,18 @@ static const struct vm_operations_struct

int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
{
- int rc, xid;
+ int xid, rc = 0;
struct inode *inode = file_inode(file);

xid = get_xid();

- if (!CIFS_CACHE_READ(CIFS_I(inode))) {
+ if (!CIFS_CACHE_READ(CIFS_I(inode)))
rc = cifs_zap_mapping(inode);
- if (rc)
- return rc;
- }
-
- rc = generic_file_mmap(file, vma);
- if (rc == 0)
+ if (!rc)
+ rc = generic_file_mmap(file, vma);
+ if (!rc)
vma->vm_ops = &cifs_file_vm_ops;
+
free_xid(xid);
return rc;
}
@@ -3264,16 +3262,16 @@ int cifs_file_mmap(struct file *file, st
int rc, xid;

xid = get_xid();
+
rc = cifs_revalidate_file(file);
- if (rc) {
+ if (rc)
cifs_dbg(FYI, "Validation prior to mmap failed, error=%d\n",
rc);
- free_xid(xid);
- return rc;
- }
- rc = generic_file_mmap(file, vma);
- if (rc == 0)
+ if (!rc)
+ rc = generic_file_mmap(file, vma);
+ if (!rc)
vma->vm_ops = &cifs_file_vm_ops;
+
free_xid(xid);
return rc;
}